Movable load support for self loading vehicle

ABSTRACT

A self-loading vehicle has a vertical swinging load support that includes a load engaging element of a fork type insertable under a pallet for loading the pallet onto the vehicle. Pivotally connected to the load engaging element is a link coupled to the vehicle by a linkage for swinging the link vertically and maintaining the link at a constant angular orientation with the horizontal during vertical swinging movement. A strut is pivotally connected to the link and engageable with a stop on the load engaging element for maintaining a horizontal position of the load engaging element during vertical swinging movement. The linkage includes an extensible link for pivoting the link connected to the load engaging element to a horizontal position which facilitates insertion of the load engaging element under a pallet with a minimum clearance.

United States Patent (151 3,666,122 Youmans 51 May 30, 1972 MOVABLE LOADSUPPORT FOR SELF Primary ExaminerPhilip Arnold LOADING VEHICLE [72]Inventor: Donald W. Youmans, San Jose, Calif.

[73] Assignee: FMC Corporation, San Jose, Calif.

[22] Filed: Sept. 9, 1970 [21] Appl. No.: 70,738

[52] US. Cl. ..2l4/77 R, 214/77 P, 214/5 l 8, 214/84, 2l4/DlG. 10

[51] Int. Cl ..B60p 1/48 [58] Field of Search ..2l4/77 P, 78

[56] References Cited UNITED STATES PATENTS 2,683,539 7/1954 Corley, Jr...2 14/77 P AttorneyF. W. Anderson, C. E. Tripp and .l. W. Edwards 57ABSTRACT A self-loading vehicle has a vertical swinging load supportthat includes a load engaging element of a fork type insertable under apallet for loading the pallet onto the vehicle. Pivotally connected tothe load engaging element is a link coupled to the vehicle by a linkagefor swinging the link vertically and maintaining the link at a constantangular orientation with the horizontal during vertical swingingmovement. A strut is pivotally connected to the link and engageable witha stop on the load engaging element for maintaining a horizontalposition of the load engaging element during vertical swinging movement.The linkage includes an extensible link for pivoting the link connectedto the load engaging element to a horizontal position which facilitatesinsertion of the load engaging element under a pallet with a minimumclearance.

6 Claims, 10 Drawing figures PATENTEBMAY 30 I972 sum 1 or 3 INVENTOR.

DONALD W. YOUMANS ATTORNEYS MOVABLE LOAD SUPPORT FOR SELF LOADINGVEHICLE BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to a self-loading vehicle and more particularly to avertical swinging load support of a fork type that is insertable under apallet for loading the pallet onto the vehicle.

2. Description of the Prior Art Existing powered tailgate lift platformsutilize a four bar of parallelogram type linkage similar to the liftinglinkage herein disclosed. When loading forks are substituted for thelift platform and the vehicle is used to position the forks under apallet, a clearance problem is often encountered. A certain amount ofspacing is required between opposite links of the lifting linkage butonly a minimum clearance is available for inserting the load engagingelements under a pallet. Should the linkage project above the loadengaging elements when these elements are elevated to the level of thevehicle load carrying surface, it would obstruct transferring a palletfrom the load engaging elements to the vehicle.

SUMMARY OF THE INVENTION Objects of the present invention are to providea fork lift that can be inserted under a pallet with a minimumclearance, that can maintain the load engaging elements horizontal whilelifting and that permits rolling a pallet onto a vehicle bed when theload engaging elements are raised to the level of the vehicle bed.

To solve the problem presented by the spacing requirement betweenopposite links of the lifting linkage and the minimum spacing availableunder a pallet, a link is hinged to the end portion of a loadingengaging element. This link is connected in the lifting linkage togetherwith an extensible link which maintains the link in a substantiallyvertical position when lifting the load engaging element. Extension ofthe extensible link pivots the link to a horizontal position forinserting the load engaging element under a pallet. A strut, pivotallyconnected to the link, underlies and is resiliently urged towards theload engaging element to engage a stop thereon for holding the loadengaging element in a fixed position relative to the link. However, thestrut disengages the stop and folds against the load engaging elementwhen the link pivots to a horizontal position for inserting the loadengaging element under a pallet.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 8-10 illustrate the operation ofthe fork lift in con-,

junction with a self loading vehicle.

DESCRIPTION OF THE PREFERRED EMBODIMENT Looking first at FIG. 8, aself-loading transport vehicle 10 is shown for lifting pallets P fromthe ground, loading the pallets onto a vehicle bed, transporting thepallets to a destination, and unloading the pallets from the vehicle.

Now looking at FIG. 1, vehicle 10 has a frame 11 with roller conveyors12 extending longitudinally thereof forming a bed for carrying loadssuch as pallets P. Triangular shaped mounting members 13 and 14 projectdownward from the frame in spaced relationship. An arm 15 is pivotallyconnected to mounting member 13 and an arm 16 is pivotally connected tomounting member 14. A brace 17 extends transversely between the armslocking them together for simultaneous pivotal movement.

Arms 15 and 16 are swung in a vertical are by an actuator 20 pivotallyconnected at one end to a transverse member 21 of frame 11. An actuatingarm 22 projects from the opposite end of the actuator and is pivotallycoupled between a pair of mounting ears 23 and 24 that project upwardfrom brace 17. When the actuating arm retracts within the actuator, arms15 and 16 are elevated and when the actuating arm is extended, arms 16and 16 are lowered.

An I-I-shaped link 27 is pivotally connected to the swinging end of arm15 and an extensible link 28, in the form of an actuator, is pivotallyconnected between the link and mounting member 13. Seen more clearly inFIGS. 5 and 6, the vertical spacing between pivotal connections of arm15 and extensible link 28 to mounting member 13 is the same as thevertical spacing between the am and extensible link to link 27. The arm,link, extensible link, and mounting member form a four bar linkage whichis a parallelogram when the extensible link equals the length of arm 15,and thus, link 27 can be swung vertically at a constant angularorientation with a horizontal.

In like manner, an I-I-shaped link 29, shown in FIG. 1, is pivotallyconnected to the swinging end of arm 16 and an extensible link 30connects link 29 with mounting member 14. The arm, link, extensiblelink, and mounting member form a four bar linkage similar to the linkagepreviously described on the opposite side of brace 17.

A tine 31 is pivotally connected to link 27 and a rectangular sleeve 33fits telescopically over the tine. The sleeve supports two parallel rowsof rollers 34 and 35 which form a roller conveying surface. While thetine alone could be used as a load engaging element for insertion undera pallet, it is preferable to have the sleeve and rollers fitted thereonforming a roller conveying surface for transferring pallets therefrom toroller conveyors 12 on vehicle 10. Similarly, a tine 32 is pivotallyconnected to link 29 and a rectangular sleeve 36 fits telescopicallyover the tine. Two parallel rows of rollers 37 and 38 form a rollerconveying surface thereon.

An attachment 40 mounted parallel with link 27 has a stop flange 41projecting upward perpendicular thereto. When link 27 is in a horizontalposition, the stop flange projects vertically to limit penetration oftine 31 beneath a pallet but when link 27 is in a vertical position, thestop flange projects horizontally below the roller conveying surfacewithout obstructing transfer of a pallet between the load engagingelement and roller conveyors 12. In like fashion, an attachment 42mounted parallel with link 29 has a stop flange 43 projecting upwardperpendicular thereto.

A strut 46 is pivotally mounted on a pin 47 that joins link 29 andattachment 42 with arm 16. As shown in FIG. 2, the strut underlies thelink and tine 32 on which a stop 48 is provided. A torsion spring 49 isfitted about pin 47 and connects the strut with the link to resilientlyurge the strut towards the tine. It should be noted that the bottomportion of rectangular sleeve 36 has been cut away behind stop 48 sothat the strut can freely engage the bottom surface of the tine. Whenextensible link 30 retracts, pivoting link 29 to a vertical position asshown in FIG. 3, strut 46 engages stop 48. The strut, link and tine forma frame of right triangular shape by which the load engaging element isheld in a horizontal position. In like manner, a strut 52 is pivotallymounted on pin 53 that connects link 27 and attachment 40 to arm 15. Atorsion spring 54 resiliently urges strut 52 towards the bottom of tine31 on which a stop 48a (FIGS. 4-7) is provided.

Operation of the load support is illustrated in FIGS. 4-7. Rollerconveyors have been omitted in these Figures from tine 31 which actsdirectly as a load engaging element. As shown in FIG. 4, extensible link28 can be extended, pivoting link 27 to a position in line with tine 31so that both the link and tine lay flat on ground surface G tofacilitate inserting the tine under a pallet P by moving vehicle 10forward. Clearance C between the ground surface and pallet may vary butmust be at least greater than the height of the tine when laying flat onthe ground surface.

After tine 31 is inserted under a pallet P, extensible link 28 isretracted to lift the joint between link 27 and the tine. As this jointis raised as shown in phantom line in FIG. 4, strut 52 slides along thebottom surface of the tine until the strut engages stop 48a. When link27 is vertical, as shown in FIG. 5, tine 31 extends horizontallytherefrom and supports pallet P. Then actuating arm 22 can be retractedwithin actuator causing arm 15 to elevate link 27 until tine 31 reachesthe bed level of vehicle 10, as shown in FIG. 6 Pallet P can then betransferred to the vehicle bed by pushing it there from the tine.Pallets can be unloaded from the vehicle in the reverse manner.

FIG. 7 illustrates other uses of the load engaging element or tine 31.Further contraction of extensible link 28 tilts the tine upward as shownin solid line. A slight upward tilt of the tine can assist intransferring a pallet from the tine to the vehicle bed and when theloaded vehicle is travelling, the upward tilted tine serves as a stop toprevent a pallet P from sliding off. Upon reaching the destination ofpallet P, extensible link 28 can be extended to tilt tine 31 downwardforming a ramp as shown in phantom line for unloading the pallet.

F168. 8, 9 and 10 further illustrate operation of the self loadingvehicle 10. The load engaging elements, including sleeves 33 and 36, arelowered to the ground surface and inserted under pallet P by movement ofthe vehicle. When properly positioned under the pallet, the loadengaging elements are elevated to the level of roller conveyors 12 onthe vehicle. Then a person assisting with the loading pushes the palletfrom the load engaging elements onto the roller conveyors of thevehicle.

Although the best mode contemplated for carrying out the presentinvention has been herein shown and described, it will be apparent thatmodification and variation may be made without departing from what isregarded to be the subject mater of the invention.

What is claimed is:

1. A vertical swinging load support comprising a load engaging element,a link pivotally connected to one end of said load engaging element, alinkage for swinging said link and said load engaging element in avertical plane and for maintaining the link at a constant angularrelationship with the horizontal during vertical swinging movement ofthe load engaging element, said linkage including an extensible memberfor pivoting the the link from its position during vertical swingingmovement of the load engaging element to a position in horizontalalignment with the load engaging element, a stop on the load engagingelement, and a strut pivotally connected to the link for engagement withthe stop to hold the load engaging element in a horizontal positionduring said vertical swinging movement, said strut being disengageablefrom the stop and foldable under the load engaging element and link whenthey are aligned horizontally to enable insertion of the load engagingelement under a pallet having a minimum clearance.

2. A vertical swinging load support as described in claim 1, includingmeans for resiliently urging the strut towards the load engagingelement.

3. In a self-loading vehicle, a vertical swinging load supportinsertable under a pallet for loading the pallet onto said vehicle, saidload support comprising an arm pivotally connected to said vehicle forvertical swinging movement; an actuator for moving said am; a linkpivotally connected to said am; an extensible member pivotally connectedto said vehicle and link for maintaining the link at a constant angularorientation with the horizontal during vertical swinging movement withthe arm and being linearly extensible to tilt the link relative to thehorizontal; a load engaging element pivotally connected to said link andhaving a stop thereon; and a strut pivotally connected to said link andunderlying the load engaging element for engagement with the stop tohold the load engaging element in a horizontal position during verticalswinging movement; said link, load engaging element and strut forming atriangular frame which collapses for inserting the load engaging elementunder a pallet.

4. A vertical swinging load support as described in claim 3,

1. A vertical swinging load support comprising a load engaging element,a link pivotally connected to one end of said load engaging element, alinkage for swinging said link and said load engaging element in avertical plane and for maintaining the link at a constant angularrelationship with the horizontal during vertical swinging movement ofthe load engaging element, said linkage including an extensible memberfor pivoting the the link from its position during vertical swingingmovement of the load engaging element to a position in horizontalalignment with the load engaging element, a stop on the load engagingelement, and a strut pivotally connected to the link for engagement withthe stop to hold the load engaging element in a horizontal positionduring said vertical swinging movement, said strut being disengageablefrom the stop and foldable under the load engaging element and link whenthey are aligned horizontally to enable insertion of the load engagingelement under a pallet having a minimum clearance.
 2. A verticalswinging load support as described in claim 1, including means forresiliently urging the strut towards the load engaging element.
 3. In aself-loading vehicle, a vertical swinging load support insertable undera pallet for loading the pallet onto said vehicle, said load supportcomprising an arm pivotally connected to said vehicle for verticalswinging movement; an actuator for moving said arm; a link pivotallyconnected to said arm; an extensible member pivotally connected to saidvehicle and link for maintaining the link at a constant angularorientation with the horizontal during vertical swinging movement withthe arm and being linearly extensible to tilt the link relative to thehorizontal; a load engaging element pivotally connected to said link andhaving a stop thereon; and a strut pivotally connected to said link andunderlying the load engaging element for engagement with the stop tohold the load engaging element in a horizontal position during verticalswinging movement; said link, load engaging element and strut forming atriangular frame which collapses for inserting the load engaging elementunder a pallet.
 4. A vertical swinging load support as described inclaim 3, wherein said link is maintained in a substantially verticalposition during vertical swinging movement and said link, load engagingelement and strut form a frame of right triangular shape.
 5. A verticalswinging load support as described in claim 3, including an attachmentmounted parallel with the link and a stop flange projecting upwardperpendicular to the attachment for limiting horizontal penetration ofthe load engaging element under a pallet.
 6. A vertical swinging loadsupport as described in claim 3 wherein said load engaging element has aroller conveyor surface thereon.